A little over a year ago, I decided to take the plunge and convert my bike into an e-bike using Clean Republic's Hill Topper kit. Overall, up until this point I've been very pleased with its performance--I live at the top of a long hill, and having the kit has cut at least 20 minutes off my commute each day. However, recently it's been dying before the end of my commute. The battery is rated for 20 miles under normal conditions, and I've owned it for about 15 months. I don't have a long commute--only about 6.8 miles all together, and the battery is only used for roughly 3.2 miles of that. But--I do use it every workday, so a rough estimate tells me I've put around 2100 miles on it.
Given the mileage, is this kind of performance drop normal? Clean Republic rates their batteries as lasting 1-2 years, so I'm within the ballpark--but buying a new $250+ battery every year or so just seems a bit excessive (and not very environmentally friendly). I'd be interested in hearing what other e-bikers think--and whether there are any other, longer lasting battery options I should consider.